/*
 *
 * Copyright (c) 2005 The Exceoon Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by the
 *        Exceoon Software Foundation (http://www.exceoon.com/)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. Products derived from this software may not be called " Exceoon ",
 *    nor may " Exceoon " appear in their name, without prior written
 *    permission of the Exceoon Software Foundation.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * Exceoon Software Corporation and was originally based on software
 * Exceoon copyright (c) 2005, International
 * Business Machines, Inc., http://www.Exceoon.com.  For more
 * information on the Exceoon Software Foundation, please see
 * <http://www.Exceoon.com/>.
 */

package com.exceoon.equals.extend.function;

import java.util.ArrayList;
import java.util.List;

import com.exceoon.equals.extend.ArrayMathematicalElement;

import fr.expression4j.basic.MathematicalElement;
import fr.expression4j.basic.OperatorManager;
import fr.expression4j.core.Catalog;
import fr.expression4j.core.Parameters;
import fr.expression4j.core.exception.EvalException;
import fr.expression4j.core.exception.ParametersException;

/**
 * Author	David.Liu 
 * Mail		david.liu@exceoon.com
 * copyright	Exceoon corporation
 */

public class MAFunction extends EconomicialFunction
{
	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * fr.expression4j.core.Expression#evaluate(fr.expression4j.core.Parameters)
	 */
	@Override
	public MathematicalElement evaluate(Parameters parameters)
	        throws EvalException
	{
		// TODO Auto-generated method stub
		return evaluate(null, parameters);
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @seefr.expression4j.core.Expression#evaluate(fr.expression4j.basic.
	 * OperatorManager, fr.expression4j.core.Parameters)
	 */
	@SuppressWarnings("unchecked")
	@Override
	public MathematicalElement evaluate(OperatorManager operatorManager,
	        Parameters parameters) throws EvalException
	{
		try
		{

			MathematicalElement x = parameters.getParameter("x");
			MathematicalElement y = parameters.getParameter("y");
			// MathematicalElement z = parameters.getParameter("z");

			if (x.getType() != ArrayMathematicalElement.TYPE)
			{

				throw new EvalException(
				        "Left element is not a ObjectArrayMathematicalElement");
			}

			// System.out.println(x);

			if (y.getType() != 1)
			{

				throw new EvalException(
				        "Left element is not a MathematicalElement");
			}

			/*
			 * if (z.getType() != 1) {
			 * 
			 * throw new
			 * EvalException("Left element is not a MathematicalElement"); }
			 */

			List<Double> data = (List<Double>) x.getValue();

			List<Double> rtn = new ArrayList<Double>(data.size());

			for (int ind = 0; ind < data.size(); ind++)
			{
				double value = 0;

				// Ft=(At-1+At-2+At-3+…+At-n)/n At-1--前期实际值

				for (int j = ind - 1, k = 0; j >= 0
				        && k < (int) y.getRealValue(); j--, k++)
				{
					value = value + data.get(j);
				}

				rtn.add(value / y.getRealValue());
			}

			return new ArrayMathematicalElement<Double>(rtn);
		} catch (ParametersException pe)
		{
			throw new EvalException("Could not find parameter x for function "
			        + getName());
		}
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see fr.expression4j.core.Expression#getCatalog()
	 */
	@Override
	public Catalog getCatalog()
	{
		// TODO Auto-generated method stub
		return null;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see fr.expression4j.core.Expression#getName()
	 */
	@Override
	public String getName()
	{
		// TODO Auto-generated method stub
		return "ma";
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see fr.expression4j.core.Expression#getParameters()
	 */
	@Override
	public List<?> getParameters()
	{
		// TODO Auto-generated method stub
		List<String> parameter = new ArrayList<String>(2);
		parameter.add("x");
		parameter.add("y");
		// parameter.add("z");

		return parameter;
	}
}
